Profiling the Transcriptome in Capsicum annuum L. Seeds During Osmopriming

Loss of vigor during seed storage causes a reduction in germinability and seedling establishment Several strategies have been developed to improve this phenomenon and one of these is osmopriming, which consists of pre-imbibing seeds in a solution containing an inert osmotic agent such as Polyethylene Glycol (PEG). PEG reduces water availability and this situation can provoke that cells in seeds reactivate metabolism but germination will not result. Thus, the beneficial effect of osmopriming is manifested as a fast and uniform germination after PEG is removed. In combination with PEG, several other compounds such as gibberellic acid and nitrate salts can be used in order to improve the vigor of seeds. In order to analyze at molecular level the effect of osmopriming seeds of chili pepper (Capsicum annuum cv. caballero) with PEG plus either Gibberellic Acid (GA sub(3)) or KNO sub(3), a profile of transcripts obtained using Suppression Subtractive Hybridization (SSH) cDNA libraries was obtained. Our results displayed the induced expression of several genes in all treatments evaluated. Some cDNA clones were sequenced and showed high similarity to genes codifying LEA and heat shock proteins, proteinase inhibitors, enzymes involved in DNA replication and proteins with unknown functions. Possible roles of some of these genes in osmopriming of pepper seeds and further germination are discussed.